t/N1=2??l1/g, t1=t2, ○¦ᄈ→│↓○ ¬│¢│:N2/N1=?l1/?l2, ᄈ¦■¥¥↓○ ¦○ ↑¬¢¦¢¢ ,
t/N2=2??l2/g
l2/l1=N12/N22=441/49=9¢
t/N1=2??l1/g, t1=t2, ○¦ᄈ→│↓○ ¬│¢│:N2/N1=?l1/?l2, ᄈ¦■¥¥↓○ ¦○ ↑¬¢¦¢¢ ,
t/N2=2??l2/g
l2/l1=N12/N22=441/49=9¢